The Pyrrhic War (280–275 BC) was a complex series of battles and shifting political alliances among the Greeks (specifically Epirus, Macedonia, and the city states of Magna Graecia), the Italian peoples (primarily the Roman Republic, Samnites and the Etruscans), and the Carthaginians. Most historical treatments of the conflict concentrate on the conflicts between Pyrrhus of Epirus and Rome. Carthage and Rome were allies in this conflict. While Carthage did, in fact, pledge aid to Rome in 280 BC, it is unclear what this aid consisted of, or how influential it was in the war. Later in the conflict Carthage was involved in its own war with Pyrrhus in Sicily. There seems to have been no coordinated military efforts between Rome and Carthage.

The Pyrrhic War initially started as a minor conflict between Rome and the city of Tarentum over a naval treaty violation by one of the Roman consuls. Tarentum had, however, lent aid to the Greek ruler Pyrrhus of Epirus in his conflict with Korkyra, and requested military aid from Epirus. Pyrrhus honored his obligation to Tarentum and joined the complex series of conflicts involving Tarentum and the Romans, Samnites, Etruscans, and Thurii (as well as other cities of Magna Graecia). Pyrrhus also involved himself in the internal political conflicts of Sicily, as well as the Sicilian struggle against Carthaginian dominance.

Pyrrhus' involvement in the regional conflicts of Sicily reduced the Carthaginian influence there drastically. In Italy, his involvement seems to have been mostly ineffectual but had long term implications. The Pyrrhic War proved both that the states of ancient Greece had essentially become incapable of defending the independent colonies of Magna Graecia and that the Roman legions were capable of competing with the armies of the Hellenistic kingdoms — the dominant Mediterranean powers of the time. This opened the way for Roman dominance over the city states of Magna Graecia and advanced the Roman consolidation of power in Italy greatly. Rome's proven record in international military conflicts would also aid its resolve in its rivalry with Carthage, which was eventually to culminate in the Punic Wars.